Visit The American Legal Ethics Library - http://library.lawschool.cornell.edu/WhatWeDo/ResearchGuides/Legal-Ethics.cfm  for excellent discussions regarding WWW ethical considerations concerning:

• Restrictions on advertising;
• E-mail;
• Newsgroup:
• Unauthorized Practice of Law.

Other notable sites:

• Legal Ethics - www.legalethics.com; 
• The National Association of Bar Counsel - www.nobc.org;